Magnetic resonance imaging (MRI) is considered to have significant potential as a non-invasive blood flow measurement technique. To date MRI of blood flow has not been fully accomplished for reasons having to do with effects arising from flow variables and from the imaging process itself. The main objective of our research is to provide quantitative tools, using computer simulation to better our understanding of MRI of flow and for use in testing and evaluation of MRI blood-flow measurement and imaging concepts. The simulation is based on the classical Bloch equation and computes the time course of magnetization for an assembly of spins moving through a vessel. Effects of both flow and imaging parameters, e.g., velocity profile, relaxation parameters, pulse sequence, field inhomogeneity and gradient fields on computed magnetic resonance signals and images will be investigated. Selective excitation and pulsatile flow modules have been recently added to the model. The evolution of the pulsatile flow profile was clearly visualized in a series of computed MR images. This research is a collaboration with the NMR Imaging group at Yale University, Dr. John Gore, Director. This group will supply experimental data for comparison with model results.